The fracture characteristics of concrete play a key roles in engineering safety. The phase-field fracture method can simulate the dynamic growth process of cracks conveniently. In this paper，the secondary development of the concrete phase field fracture method based on Abaqus was realized by using UEL and UMAT subroutines，the influences of element size and length scale parameters on crack propagation width of concrete beams were analyzed in the three-point bending test. The results show that the crack width is not affected by the element size until it is small enough and the crack width decreases with the decrease of length scale parameter.